Oct 8 - SUS - System Usability Scale

System Usability Scale (SUS)

About SUS
SUS is a 10-item questionnaire that employs a Likert scale to obtain an overview of user satisfaction with software. It was developed by John Brooke to: provide an easy test for subjects to complete (i.e. minimal number of questions), be easy to score, and allow cross-product comparisons.

Contact:
John Brooke, Redhatch Consulting Ltd., 12 Beaconsfield Way, Earley, READING RG6 2UX, United Kingdom, email: john.brooke@redhatch.co.uk

References:
1) SUS – A Quick and Dirty Usability Scale, John Brooke, Redhatch Consulting Ltd., United Kingdom
2) Bevan, N, Kirakowski, J and Maissel, J, 1991, What is Usability?, in H.-J. Bullinger, (Ed.). Human Aspects in Computing: Design and use of interactive systems and work with terminals, Amsterdam: Elsevier.
3) Kirakowski, J and Corbett, M, 1988, Measuring User Satisfaction, in D M Jones and R Winder (Eds.) People and Computers IV. Cambridge: Cambridge University Press.
4) Pratchett, T., 1990 Moving Pictures. London: Gollancz
5) http://www.usability.serco.com/trump/documents/Suschapt.doc
6) http://www.ucc.ie/hfrg/resources/qfaq1.html#whatswrongwithputting

Source: http://www2.hf.faa.gov/workbenchtools/default.aspxrPage=Tooldetails&subCatId=13&toolID=255


About SUS

The System Usability Scale (SUS) in systems engineering is a simple, ten-item attitude Likert scale giving a global view of subjective assessments of usability. It was developed by John Brooke at Digital Equipment Corporation in the UK in 1986 as a tool to be used in usability engineering of electronic office systems.

The usability of a system, as defined by the ISO standard ISO 9241 Part 11, can be measured only by taking into account the context of use of the system — i.e., who is using the system, what they are using it for, and the environment in which they are using it.

Furthermore, measurements of usability have several different aspects:
effectiveness (can users successfully achieve their objectives)
efficiency (how much effort and resource is expended in achieving those objectives)
satisfaction (was the experience satisfactory)

Measures of effectiveness and efficiency are also context specific. Effectiveness in using a system for controlling a continuous industrial process would generally be measured in very different terms to, say, effectiveness in using a text editor. Thus, it can be difficult, if not impossible, to answer the question “is system A more usable than system B”, because the measures of effectiveness and efficiency may be very different. However, it can be argued that given a sufficiently high-level definition of subjective assessments of usability, comparisons can be made between systems.

SUS has generally been seen as providing this type of high-level subjective view of usability and is thus often used in carrying out comparisons of usability between systems. Because it yields a single score on a scale of 0-100, it can be used to compare even systems that are outwardly dissimilar. This one-dimensional aspect of the SUS is both a benefit and a drawback, because the questionnaire is necessarily quite general.
It has been widely used in the evaluation of a range of systems.

References:
Brooke, J. (1996) SUS: a "quick and dirty" usability scale. In P. W. Jordan, B. Thomas, B. A. Weerdmeester & A. L. McClelland (eds.) Usability Evaluation in Industry. London: Taylor and Francis. "Online copy". http://www.usabilitynet.org/trump/documents/Suschapt.doc.

Source: http://en.wikipedia.org/wiki/System_Usability_Scale